G22.2590 - Natural Language Processing  -- Spring 2006 -- Prof. Grishman

Assignment #2

January 24, 2006

(1) [1.5 points] Using the grammar given in sections 9.1-9.5 of J & M, determine the constituent structure of the sentences

a) Show the airlines with flights to Boston.
b) Show the airlines that fly to Boston.
c) I need to know the aircraft and flight number.
d) Do you prefer to go to Boston?
You do not have to account for agreement (p. 340-41) or subcategorization (p. 344).  If you don't want to draw trees, you can use parenthesis notation ("[S  [NP  [Nominal  [Noun flights]]] [VP [Verb crash]]]").  The grammar given in sections 9.1-9.5 is summarized below.

Keep in mind that our goal in parsing a sentence is to get some handle on the meaning (semantics) of a sentence through its syntactic (grammatical) structure. The subject of a sentence (the np in s->np vp) and the object of a sentence (the np in vp -> v np) should in general reflect the 'who did what to whom' relationships.  In addition,
(2) [1.5 points] J&M 9.3:  Augment the rules of the J&M grammar in the manner described on page 341 to handle pronouns.  Deal properly with person/number and case (this means that your grammar should block both errors of number such as *"He eat" and errors of case such as *"Him eats."). 
     Your grammar does not have to account for the special form of "be" for first person singular ("I am").  All other verbs have at most two present tense forms;  in consequence, it is sufficient for purposes of person/number agreement to lump together 1st person singular ("I"), 2nd person singular ("you"), and all the plural pronouns ("we", "you", "they"), and distinguish them from 3rd person singular pronouns ("he", "she", "it").  In addition, to capture the case constraints, you must distinguish nominative ("I", "he", "she") from accusative ("me", "him", "her") pronouns, keeping in mind that some ("you", "it") can fill either case.

(3) [1 point] Using Jet (with grammar grammar1.txt) add a verb and a noun to the dictionary given (tiny1.dict) and parse two sentences,  using the top-down parser; submit the parses produced (copy and paste from the console log).  Download Jet and follow the Jet Guide for Assignment 2.

Due January 31st.


Summary of Jurafsky and Martin English Grammar (Chapter 9, sections 1-5)

S
->
NP VP |


VP |


Aux NP VP | Wh-NP VP | Wh-NP Aux NP VP |


S and S
NP
->
Pronoun |


Proper-Noun |


(Det) (Card) (Ord) (Quant) (AP) Nominal |


NP and NP
Nominal
->
Noun Nominal | Noun | Nominal PP (PP) (PP) |


Nominal GerundVP | Nominal RelClause
VP
->
Verb | Verb NP | Verb NP PP | Verb PP | Verb S | Verb to VP |


VP and VP
PP
->
Preposition NP
GerundVP
->
GerundV | GerundV NP | GerundV PP | GerundV NP PP
RelClause
->
(who | that) VP